This invention relates generally to protective gloves and more particularly to chemical-resistant protective gloves.
Polymers such as polychloroprene, acrylonitrile, natural or synthetic isoprene, and butyl rubber provide relatively inexpensive and useful materials for making protective gloves. Gloves can be made by injection molding or by dipping a glove former into a vat of such polymers.
Because polymers have different characteristics, it has in the past been found useful to make composite gloves of successive laminations of different materials. U.S. Pat. No. 5,459,880, for example, teaches that a glove with high strength and oil resistence can be made at a low cost by successively immersing a glove former in two different rubber latexes.
It is also known that some fluoroelastomeric materials, such as the commercially-available VITON(copyright) or TECHNIFLON(copyright) fluoroelastomers, can be used to provide improved chemical resistance to a wide variety of toxic corrosive chemicals and solvents, radiation, and flammablity. U.S. Pat. No. 4,218,779 describes the desirability of using such materials as the outer layer of a protective glove.
Unfortunately, the cost and physical characteristics of many fluoroelastomeric materials make the conventional successive-immersion process impractical as a method for applying a fluoroelastomeric coating on a glove. Apparently unable to find a cost-effective way to add a thin layer of fluoroelastomeric material over a less-expensive polymeric base, some manufacturers have chosen to make gloves entirely of the more expensive fluoroelastomeric material.
Fluoroelastomeric materials tend to create a very smooth, slick surface on gloves. This surface reduces grip when handling wet objects. The smooth, slick surfaces of such gloves also tend to adhere to one another when the gloves are packaged, making it difficult to subsequently separate the gloves. In order to overcome adhesion problems and to allow the gloves to don more easily, most fluoroelastomeric gloves are powdered inside.
There is a long-felt need for a cost-effective way to add a thin layer of fluoroelastic material over a polymer glove base, and for a fluoroelastomer-coated glove with a non-adhesive finish that will increase wet gripping and allow the gloves to be sold free of powder.
The invention relates to a mounting fixture that can be used to make gloves having a thin layer of a fluoroelastomeric material on the outside surface of a polymeric glove base. The fluoroelastomeric coating is the dried product of a water-based fluoroelastomeric material that is sprayed onto the glove base during manufacture.
Spraying a finished polymeric glove base with a conventional, solvent-based fluoroelastomeric material could result in the solvents damaging the glove base. Further, spraying a glove base while it remains on a glove former on which the glove base is made would he undesirable because gloves are conventionally formed inside-out on the formers; the surface of the glove next to the former generally becomes the outside surface of the completed glove, while the surface of the glove that faces outwardly while the glove is on the former becomes the insider surface of the completed glove. Accordingly, spraying a glove base while it is still on the former would lead to the fluoroelastomeric coating being applied to what will become the inside surface of the completed glove. Since one of the purposes of the fluoroelastomeric material is to protect the less-resistant polymeric base from external chemicals, applying the fluoroelastomeric material to what will become the inside surface of the completed glove is not particularly desirable. A second problem is that the fingers on the former are too close together to allow easy spraying. Further, material that is oversprayed onto the glove former could spoil subsequent glove bases made on that former.
A novel mounting fixture has been developed to enable a thin fluoroelastomeric layer to be sprayed on the outside surface of a glove base. After the glove base is first prepared, cured, and removed from its former, it is placed on the mounting fixture with the final outside surface facing out. The fixture has a seal and a sealing ring for sealingly engaging the open end of the glove base. It also has a means for inflating the glove base while it is on the mounting frame. Inflating the glove causes the fingers to spread, making it easier to cover the surface of the glove base with the spray.
After the initial coating is applied, a final, atomized spray of the fluoroelastomeric material can be used to give a matte finish to the completed glove. The matte finish does not have the adhesive characteristics of conventional fluoroelastomic gloves, facilitating handling.